Range finding unit, including a viewing range finder and a light beam projecting range finder for photographic purposes



Feb. 8, 1955 M. SCHWARTZ ET AL RANGE FINDING UNIT, INCLUDING A VIEWING RANGE FINDER AND A LIGHT BEAM PROJECTING RANGE Filed March 9, 1951 FINDER FOR PHOTOGRAPHIC PURPOSES v 2 Sheets-Sheet l V EN TORS Feb. 8, 1955 M. SCHWARTZ ET Al. 2,701,500 RANGE FINDING UNIT, INCLUDING A VIEWING RANGE FINDER AND ALIGHT BEAM PROJECTING RANGE FINDER FOR PHOTOGRAPHIC PURPOSES Filed March 9, 1951 2 Sheets-Sheet 2 4 www,

Afm/eww.

United States Patent tRANGEEFINDING tINCLUDING A fVIEWING vFENDER AND -A iLIGHT BEAM "PRO- JECL'IN GTRA'N DERfFOR'PHO T0 GRAPHIC iPURROSES Morris :Schwartz yand JWilliam -Castedeilo, Piainvilla .Conn.,i.assignors:to -Ihe Kaiart Company A`Inc.,-Plain \ville,.-Conn.

.ApplcationMarch-9, 1951, Serial No. k214,"f73'6 I5*4 Claims. -{Cl. "8S-'214) lhisf'inven't'ionrelatestoa viewing rangen'der an'd a lightbeamprojecting range-'finder -unit for photographic purposes, :particularlytoafunitof this type designedffor mounting within ther'casingof =a photographic camerai and controlled bythe ffocusingmovement of the camera lens.

It will be evident, that the space availableintne vcasing 'of `a camera,l even o -a y'comparatively vlarge. camera tsuch as a so-'called 4press camera, fis'vra-ther limited. As :a re- Sult,fity is ditticulttroma'manufactur'ing view Ypoint'to find room for'all the -necessary components 'ofthe" tinderswith out -reducing thefindividual t components to a "size which makes the same tooldelicate 4and zintert'eres'with@2t-satisfactory range iinding foperation.

'One of tne ohJects ortnejpresent invention is to provide a' comoinationunit ot the general type, abovef reierre'cltto, -wnich is soY compact'l in ydesign that-*it can befconveniently titten in the spacegeneraily yava'ilable'n 'a :cameracasing without lsacrin'cing r-the accuracy and vreliability yof the rangetnding operation and without reducing the sharpness of vision through thefsystem.

Another oo1ect=or=the invention is toprovide a'- novel and improved combination unit of thegen'eral'type, above referred` to, which is simple lindesign Varx'tivrequires comparativ'eiy: few 4individual t components. Theseadvantages are .attained by structurally-combinmgsome kof fthe optical components of theviewmgw'range iinder and the light beam projectingrangender.

lanother fmorespec`iic objectof the finvention, allied with Ithe preceding one, is -to reduce the total space occup'iedl-bythe two range Fndersfby arrangingsome ofthe nndercompone'nts one above the other andoyafn'ovel =ar rangementfofi the'imagefforming lenses of the; light beam prolectingrangender.

"Uther and'rurtnerfobjects, features and advantagesof theinventionvs'iill be'pointed outhereinafter andfset or'th infthe appended claimsfforming part o'f the application.

ln 'the accompanying'drawing a-now preferred embodiment of `the invention lis shown by way 'oli illustration an'd not by-wayof limitation.

"lnfthe drawing: p

fFig. 'l iis a plan view of La lens ycoupled-'range n'ding combination-unit according -to the invention.

.iF ig. -2 is an Aelevational sidelvliew of Fi/g. l1.

`fFig.-'4' f1's a section takenon line vofl'rlig. -2.

l1-iig. 5 'is'a section offthe lamp 'holder on an'enlarged sc e.

F 'Fig.'6 is-a' plan view ofFig. 5v-seen along lne6-6 Vof ig.f'5.

fFig. 7 isiadiagramtof-the optical system ofthe viewing range -lnder, and

'Fig. 8 is adiagram. of the-light beam projecting range n'cler-'ofthe unit. y

Referring first -tof-Figs. ljto "6, fthe entire 4rarrgelinding unit is'mounte'd -upon La base plate 10 which should be visualizedas a'partition -wall in a camera casing. The

stationaryreectorfof 'the-viewing range n'der is desigf.

nated"by1-1land the stationaryreector of the light ybeam projecting range nder is designated by .1^2. Reflector ,11 is -a semitransparent'mirror landfpartially ,coated for 'this purpose. "Mirrorll acts as'a'beam splitter in'a conventional manner. "Reflector i12 is a solidly silvered mirror. The pivotal reflectors of the two'range finders are-'formed byja common-reector 13 shown yas a'prsm.

'The --opticl components *of the viewing range finder further comprise -a;-stationary 'reector y14 shown as a rice lprism-whichreects images-viewable'on the beam' splitter to val'stationary reliector 1'5`thaving 1a reflecting surfface'l. TheA position lofthe/eye of thefobserver is indicated-atti?.

The light "beamj projecting range fnder comprises, in addition to the aforementioned components, an "image 'forming lens 18 disposed'in the v"optical center aXisbetween mirror 12 andprism 'ltyand` animage forming lens '19 disposedbetween mirror 1111an'd'an exterior object,"th'e rangeof which-isto be" determined. Thelast mentioned yrange tinderfurther'includes 'a source of'light shownfas an 'incandescent'-lightbulb, generally"designated vby 20.

VThe common prism x13 `is pivoted by moving'means, :generally designated by `2'1. These movingfmeans fare controlled in a conventional manner 1-`by"the focusing movement of `"the-camera'lens `and should bevsualized as being'coupled with 'thelens cariierby means of-a shaft-22 which vis rotated'by `a displacement 'of-the'lens'carrier on the fcamera bed. It isl'believedt-hat the 'coupling'fbetween shaft y22and the lens camera 'is not= essential- Ifor y`the= un- `derstantlingof the zinvention'an'd it is, therefore, Enot Y shown in detail. V

Referring no'w -to ZFigs. 7 yfand 8,Fig."7 showsaftlia gram-of 'the optical system of the viewing 5range finder-and TF ig. `8 of lthe lighfbeamf projecting range "finden As will be apparent yfrom'lFig. 7, a light beam reaching beam splitter 11 `fromfatrexter'ior -object to be'observe'd will -pass through 'the"fbeam vsplitter Aand 4is reected'by .,p`risms1i'41andf15`fto Vthefeye'117 l-o`f theobserver. `A second beam from the object will `be lreflected-Eby,pivotal Iprism 113 to'ibeamsplitter1l1, then by `the beam'splitter to; prism 114, andnally by'piisml14"to1prism15. IAS a result, fan observer can view two images-ofthe objectfon 'the reecting surface 16 of `prism 15, the relative-position o'f the two imagesbeing fcontrolle'd by I'the angular `position fo'f prism 13 which, in tur-n, isfcontrolled"'by-theffocusing movementoffthelens 'in -a Emanner. well -un'derstoo'din y'the art.

According to'fFig. v8,-fa=lightbeam `will be projected toward' the object'by-lstationary mirror 12through` lens XL19 and a secondflight'beam `through -lens 18 'by pivotal' prism `13. As'will be obvious, dueto'the image "forming-lenses 178 and 19, 'the observer-willsee twoimages of the lament of lamp 20 on 'the object, :the relative positionvof saidlimagesbeing again controlled by thefangular positioni ofy prism 13.

Rever'tinglagainff'to Figs. l Eand v2 `and also referringlto 'the companion Figs. 3,54, 5 and 6, thestructuralfeatures of therangeznding unit will now'be describedl in detail.

As can best beseen' on Fig. la bracket o'rblock 12'5is iixe'dly secured tojrbase vplate `r11). This block has `a slanted side wall-'to which is :secured mirror12'fby2any1suitable meanssuch=asscrews 26. 'The top of'blockZS is at and supports the mountings of beam splitter11 andprism 14. Beamvsplitter 11 an'd prism `14 'can 'be mounte'd in any suitable manner, #afram'e r27 and a"bracket 28 being indicated by way of illustration. It s lessential to note in this connection that mirror 12 and beam splitter Il'are mounted substantially -one above the other, mirror 12 being disposed yat Ithe lower level relative to the `base plate 10. Prism 141isdisposed vin the upper level and in substantially 'the same horizontal plane with lbeam splitter 11.

Block 25may'ffurther support a-shield '30 which serves topreventstray lightv tol-enter the section o'f the compartment to the le'ft'offthe optical systems ofthe range finders (as seen in Figs. `1 and v2;) which section may serve to house for instance the optlcal system of' a View linder.

`Prism 13, which of course could be replaced by a mirror, ispivotally mounted on the base plate by means of a bracket 35 and `pivots about afshaft 36. VAs Vcan best be seen on Fig. 2, prism 13 is elongated to extend .l through the level of mirror 12 to the level of beam splitter 11. While it is preferable and valso shownto make prism 13 out of one piece, it will be apparentthat this prism could also be made of two sections, one on top of the other. Prism 13 is secured-to a suitable mount* f ing 37 which pivots together with the prism and is attached to or integral with a lever 38 the free end of which supports a pin 39 coacting with a cam or wedge surface 40 of alever 41. This lever is slidably guided between a rib 42 of base plate llla'nd'a nger-f43vsecured to rib 42 for instance by a screw 44. Lever 41 is further ,mission between the rotation of shaft 22 and the angular position of prism 13. One arm of a two-arm lever 46 is pivoted to lever 41 by a pivot pin 47 and the other arm of this lever is pivoted by a pivot pin 48 to an arm 49. Lever 46 is pivotal about a pivot 50. Arm 49 is pivoted to an arm 51 which in turn is fixedly secured to shaft 22, for instance by means of a screw 52. Springs 53 and 54, secured on one end to base plate 10 and on the other end to arm 51 and lever 41 respectively, load the entire system Sothat wedge surface 40 is always biased against pin 39 and a notch 55 isbiased against a limiting edge 56 of lever 46.

The entire hereinbefore described system of moving means 21 is mounted in the lower level or plane or closely adjacent to base plate 10. As will be apparent, a certain angular rotation of shaft 22 will result in a corresponding pivotal movement of prism 13, thereby jointly varying the angular position of the pivotal ret flecting surfaces of both the range finders.

Image forming lens 18 is secured to base plate 10 by means of a mounting 60 which can be adjusted in the direction of the optical axis of the lens by means of an elongated slot 61 and a screw 62. Similarly, lens 19 is secured to block by means of a mounting frame 63 and can be adjusted in the direction of its optical axis by means of an elongated slot 64 and a screw 65 engaging a bracket 66 secured to block 25.

A mask 70 on the lower half of prism 13 limits the effective reflecting surface of this prism in accordance with the diameter of lens 18.

Lamp 20 is inserted in a lamp holder of suitable design. This lamp holder is shown as comprising a metal sleeve 71 which is rotatably fitted in a wall 72 which may be visualized as part of the camera casing. Sleeve 71 supports an insulation sleeve 73 in which is fitted a metal sleeve 75 which serves to receive the base of lamp 20. The terminals of the lamp are connected in a conventional manner to a source of current, usually a battery disposed within the camera casing. The entire lamp holder can be rotated by means of a knurled head 85 accessible from the outside of the camera. To secure the holder in a selected rotary position an insulation block 86 is secured by screws 87 to a bracket extending from base plate 10 (not shown). The insulation block supports two springs 88 and 89 secured to block 86 by screws 90. These springs engage frictionally sleeve 73 thereby holding the lamp holder in position. A pin 91 extending from sleeve 71 and engageable with a stationt ary stop 92 secured to base plate 10 or part of the camera casing serves to limit the rotational movement of the lamp holder.

The globe of the lamp extends into an axial bore 93 of a block 94 made of opaque material and secured to base plate 10. Block 94 further includes two channels or bores 95 and 96 extending from the central bore 93 and positioned in alignment with the lamp filament 74 and thel optical center axis between reflectors 11 and 13. Lamp 20 isof the type having a filament 74 in form of a substantially cylindrical coil and is so inserted in the lamp holder that the long axis of the filament coil is parallel to the aforementioned optical axis. As a result, the two images of the lamp filament which are projected by the light beams of the range finder appear as circles which can be conveniently and accurately placed in a superimposed position.

As previously mentioned, frame 27 of the beam splitter 11 of the viewing range finder is mounted on the top of block 25. The position of the beam splitter can be adjusted by means of a screw 76. Rotation of this screw by means of a crown wheel 76 causes the beam splitter to be tilted slightly in its own plane for purposes of adjustment.

The reflecting prism 14 of the viewing range finder is also mounted on block 25 or more specifically on a raised portion 25 thereof so that prism 14 is at the correct level relative to the beam splitter, as can best be seen on Fig. 3. The viewing prism 15 of the viewing range finder is mounted on the same level as prism 14 by means of a post 77 vsecured to base plate 10. A mask or screen 78 may be provided to prevent stray light from lamp 20 to reach prism 15 and to disturb thereby the observer when viewing the images on the prism. The optical systems of the range finders may furtherrbe shielded against straysight by a shield secured to base plate 10 by an ear As will appear from the previous description, the optical systems of the two range finders are disposed in two different planes parallel one to the other. The only movable optical components of the two finders, namely the pivotal reflector, are combined in the single element 13 so that the same moving means 21 can be used for the pivotal reflectors of both the finders. Furthermore, one of the image forming lenses is disposed between the respective reflectors. Finally, the provision of the reflectors 14 and 15 permits to view the two images of the viewing range finder in a position very closely adjacent to the position normally loccupied by the eye of the observer when the observer uses the View finder of a camera of the type 4here in question. lThis view finder, as previously mentioned, may be visualized as being disposed in the compartment to the left of shield 30. As a result, only a slight shift of the eyeball of the observer is necessary to switch from the viewing operation to the range finding operation.

The result of the aforedescribed structural arrangement of all the optical and mechanical components of the range finders is a very compact design which can be convenientlyvmounted within the available space of a camera casing without requiring an undue reduction of the size of the individual components.

While the invention has been described in detail with respect to a certain nowpreferred example and embodiment of the invention it will Vbe understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing `from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A Yphotographic range finding unit comprising a viewing range finder and a light beam projecting range finder, the said viewing range finder including a semitransparent stationary reflectorn through which an image of an object exterior to` the Vsaid range finder is viewable, a pivotal reflector disposed in optical and spacial alignment with the stationary reflector so as to reflect a second image of the exterior object to the stationary reflector, and reflecting and viewing means optically associated with the stationary reflector for viewing the said two images; the said light beam projecting range finder including afstationary reflector, a pivotal reflector, a holder for a source of light disposed between the two reflectors of the light beam projecting range finder, the said stationary reflector, the said pivotal reflector and the said holder of the light beam projecting lrange finder being disposed in optical'alignment an image forming lens between said light holder and the respective pivotal reflector in optical alignment therewith, and a second irnage forming lens between the respective stationary reflector and said exterior object'in optical alignment therewith, thereby causing each of the two reflectors of the l1ght beam projecting range finder to reflect a light beam emanating from a source of light lin said holder toward the said exterior object, respective reflectors of the two range finders being disposed one above the other substant1ally in alignment one with the other, the said pivotal reflectors of the range finders being formed by a single pivotally mounted reflecting member including a light de viating surface having a portion in optical and spacial allgnment with the stationary reflectoriof `one of the range finders for the purpose aforesaid and a second portion in optical and spacial alignment with the stationary reflector of the other range finder for the purpose aforesaid, and moving means coupled with said pivotal member for varying the angular position of the said pivotal reflectors.

2. A range finding unit as defined in claim l, wherein the aforementioned components of one of said range above the rst layer, and wherein said light deviating surface of the pivotal reflecting memberextends through both said layers.

3. A range finding unit as defined in claim 2, wherein the said pivotal reflecting member is a single prism elongated to extend through beth said layers having their reflecting surfaces in the same plane.

4. A range nding unit as defined in claim 1, in combination with a base plate on which said pivotal reflecting member, a bracket having a side wall and a top wall, said image forming lenses, said moving means, said reecting and viewing means, and said light holder are mounted, said bracket supporting on said side wall the stationary deflector for the light beam projecting range finder and on its top wall the stationary reflector for the viewing range finder.

5. A range finding unit comprising a base plate, a viewing range finder and a light beam projecting range finder mounted on said base plate, the said viewing range finder including a semi-transparent stationary reflector through which an image of an object exterior to the said range nder is viewable, a pivotal reflector disposed in optical and spacial alignment with the stationary reilector so as to reflect a second image of the exterior object to the stationary reector, and reecting and viewing means optically associated with the stationary reflector for viewing the said two images; the said light beam projecting range nder including a stationary reflector, a pivotal reflector, a holder for a source of light disposed between the two reflectors of the light beam projecting range finder, the said stationary reflector, the said pivotal reector and the said holder of the light beam projecting range finder being disposed in optical alignment, an image forming lens between said light holder and the respective pivotal reflector in optical alignment therewith, and a second image forming lens between the respective stationary reflector and said exterior object, thereby causing each of the two reectors of the light beam projecting range finder to reflect a light beam emanating from a source of light in said holder toward the said exterior object, the reflectors and the viewing means of the viewing range finder being disposed substantially in one layer parallel to the base plate, and the reectors, the lenses and the light holder of the light beam projecting range finder being disposed in a second layer situated between the said rst layer and the base plate parallel to the first layer and the plate, respective reflectors of the two range finders being disposed one above the other substantially in transverse alignment relative to said layers, the said pivotal reflectors of the range iinders being formed by a single pivotally mounted reflecting member including a light deviating surface having a portion in optical alignment with the stationary reflector of one of the range finders and a second portion in optical alignment with the stationary reflector of the other range finder, both said portions being in one plane, and moving means coupled with said pivotal member for varying the angular position of the said pivotal reflectors, the said moving means being disposed substantially in the second parallel layer.

References Cited in the le of this patent UNITED STATES PATENTS 1,489,838 Kohler Apr. 8, 1924 2,101,543 Henkel Dec. 7, 1937 2,151,124 Leitz Mar. 21, 1939 2,376,982 Schwartz et al May 29, 1945 2,379,698 Fischer July 3, 1945 2,397,160 Schwartz et al Mar. 26, 1946 2,403,308 Schwartz et al. July 2, 1946 2,547,232 Schwartz et al. Apr. 3, 1951 

